Marketing services group WPP reported an 8.3 per cent increase in profit before interest and taxes for its PR and public affairs division to £65m ($108m), up from £60m ($99m) for the same period last year.

Stronger growth in the UK and North America helped like-for-like net sales increase 3.5 per cent in the second quarter to £221m ($366m).

Burson-Marsteller, Cohn & Wolfe and the specialist public relations and public affairs businesses performed particularly well, according to WPP’s interim financial report, published today.

PR and public affairs had the highest margin out of WPP’s four business streams (the other three being advertising and media investment, data investment and branding, healthcare and specialist comms), at 15 per cent, up from 13.2 per cent last year.

However, WPP’s overall financial performance was hampered by the recent rise in the value of sterling against other currencies.

Its reported net sales (a measure the company claims is more appropriate than revenue) were down 1.9 per cent to £4.79bn ($7.94bn); on a constant currency basis they would have increased by 6.4 per cent.

Nevertheless, group pre-tax profit jumped by 15 per cent to £491m ($814m).

Commenting on the outlook, WPP said its operating companies were hiring cautiously and that while clients may be more confident than they were in September 2008, they broadly remain unwilling to take further risks, particularly given so many political flashpoints in places such as Ukraine, Gaza and Iraq.

An earlier version of this article incorrectly stated that WPP's PR operating profit had increased by 13.2 per cent.